Photographic printer mechanism



Oct. 6, 1942. K, POLHEMUS 2,298,097

I PHOTOGRAPHIC PRINTER MECHANISM Filed Aug. 2, 194o 2- Sheets-Sheet 2INVENT OR.

JOH/V P0 EMA/J ATTORNEY 5 Patented Oct. 6, 1942 UNITED STATES PATENTOFFICE PHOTOGRAPHIC PRINTER MECHANISM John K. Polhemus, Binghamton, N.Y., assignor to General Aniline & Film Corporation, Binghamton, N. Y., acorporation of Delaware I Application August 2, 1940, Serial No. 349,575(01. 95-13) 3 Claims.

This application deals with a photographic printing apparatusand moreparticularly with a novel combination latch and electric switchmechanism for such a printer.

Printers are well known in the prior art, which comprise a lamp house, asuitable transparent supporting platen for the material to be printed,and a pressure back for holding said material against the platen. Insome of these printers electric switches have been provided whichcooperate with the pressure back to illuminate the printing lamps as theback moves into position against the platen. With this type of switch itoften happened that the printing 'lights were turned on beforethe backwas completely in position.

With the defects of these prior art constructions in view, it isaccordingly one object of the present invention to provide a novelswitch mechanism for a photographic printing apparatus.

It is a further object to provide a switch which will not be operateduntil the customary pressure back has been completely moved to itsholding position against the supporting platen.

Another object is to provide a combination latching mechanism and switchfor the pressure back on such a printer.

A still further object is to provide a latch and switch which willcooperate to illuminate the printing lamps only after the operating armfor the pressure back has been fully depressed and then moved partlyaway from the platen again.

Further objects and advantages will be apparent from the followingspecification.

In the drawings, which form a part of this application and in which likereference characters indicate like parts:

Figure 1 is an enlarged sectional view of a combination latch and switchaccording to the present invention, said latch being in locked positionand said switch closed;

Figure 2 is a view similar to Figure 1, but with the latchin releasingposition and the switch open;

Figure 3 is an enlarged sectional view on the line 3-3 of Figure 1; and

Figure 4 is a perspective View of a complete printer embodying theconstructions shown in the previous figures.

In order that those persons skilled in the art may fully understand thenature and scope of the present invention, I shall now give a conciseand detailed description thereof. As shown in Figure 4, I have provideda suitable supporting frame I for the customary lamp house 8. Print- 55ing lamps 9 are mounted in said lamp house in any desired manner. Abovethe frame and lamp house is a suitable supporting platen Ill on whichthe printing material is to be placed. In order to hold said material inprinting position against said platen, I have provided the pressure backI I. This pressure back is linked to operating arms I2 by means of thecontrol linkage I3. Arms I2 also carry resilient members I4-for engagingthe pressure back II and insuring an even contact against the platen.

Operating arms I2 are pivotally mounted with respect to the platen andare provided with a horizontal handle bar l5 at the front of theapparatus. Pivoted to the handle bar I5 is a latch I6 which is movablebetween .locking and releasing positions under the influence of releasebar IT. The construction of the pressure back, operating arms, and latchis fully described and claimed in the joint application of the presentinventor and Bror W. Henrikson, for Pho tographic printing device,executed July 31, 1940, Serial No. 349,577. The particular pressure backmechanism of said application is extremely advantageous in combinationwith the switching device of the present invention.

As described in the above mentioned application, the latching member I6is rotatable between the locking position of Figure 1 and the releasingposition of Figure 2, by the action of release bar II in cam slot I8 onthe latching member. The latch member is further hollowed out at I9 toaccommodate the spring 20 which normally urges the release bar, andconsequently the latching member, to the locking position of Figure 1.This spring is fastened at one end to the release bar and at the otherend to a lug 2I in the latch member. the swingable arms 25 pivoted tothe operating arms I2.

It will be apparent from the above mentioned application and from theforegoing description, that movement of the operating arms I2 and handleI5 away from the platen ID will carry the pressure back out ofengagement with the platen by reason of the control linkage I3.Similarly, as handle I5 is moved-toward the platen, the back I I willmove into platen-engaging position. After the back is completely incontact with the platen at all points, it is still possible to depressthe handle I5 and arms I2 for a limited additional distance toward theplaten. This additional movement will be permitted by the controllinkage I3 and will be opposed by the resilience of spring members I4.As soon as the handle is The release bar I'I itself is carried bysuitable circuit.

released, it will tend to undergo a return movement under the action ofsaid spring members. The advantages of this permissible additionalmovement in connection with my novel switching means will be describedbelow.

The latching member I6 is provided with a latching hook 22, whichcooperates with a corresponding locking element 23 on the downwardly.

turned flange 24 of platen Hi. It will be apparent from the drawingsthat, as the operating arms 12 move toward the platen, the latching hook22 will come in contact with the top edge of the flange 24. When theoperating arms are moved toward the platen for the additional limiteddistance mentioned above, the hook will ride 'over this portion .of theplaten by reason of its particular shape and will, in so doing, rotatethe latching member l6 toward its releasing position against the actionof spring 20. When the downward movement of arms 12 is complete, springwill restore the latch member and latching hook to their normal positionin which the hook 22 will be directly below the corresponding lookingelement 23 and will be ready to engage said element when the arms [2 andlatch l6 move upwardly. The necessary limited upward or return movementis obtained by the action of springs 14 previously mentioned.

According to the present invention, I have mounted a switch-actuatingmember 26 in a position to be engaged by the locking book 22 as saidhook moves upwardly into latching position. This member 26 is pivoted at21 to a bracket 28 fastened to the platen or frame. One end 29 of member26 projects forwardly, as shown in Fig ures l and 2, and is free to movevertically in the path of locking hook 22 and adjacent the lockingelement or surface 23. Thus, as the hook 22 moves upwardly againstsurface 23, it will engage the end 29 of member and rotate said memberin a clockwise direction in the drawin s.

The opposite end 30 of member 26 is provided with a switch-engagingscrew SI and locking nut 32 and also with a limiting screw 33 andadditional locking'nut 34. The function of these parts will be describedin a moment.

In the preferred form of my invention, I have mounted a mercury switch35 '(having the usual lead wires 36) on a rotatable lever 31 by means ofa suitable bracket 38 (Figure 3). Said lever 31 is pivoted at 39 to aflange All on the platensupporting frame. Said lever 31 is provided atits other end with a horizontally turned flange or lug M, which ispositioned just below the screw 3| on actuating member 26.

It will be apparent from the description just described that theclockwise movement of lever 26 will cause the lower end of screw 3| toengage the pivoted lever 37 and move said lever from the dotted lineposition of Figure 3 to the heavy line position in said figure. Themercury switch 35 is so mounted that this rotation from the dotted lineto the heavy line position will make the necessary electrical contactbetween the terminals of lead wires 35 and thus illuminate the printinglamps 9, connected to the switch by a The limiting screw 33 with itslocking nut 3 will engage the underside of platen ID, as shown in Figure2, to limit the counter-clockwise rotation of member 25. Thus the openposition of switch 35 and lever 37 will alsobe determined.

Since the end 29 of actuating member 25 is only engaged by the lockinghook 22 of latch member l5, after said latch member and the operatingarms I2 have been depressed the additional distance previouslymentioned, it is obvious that switch 35 cannot be actuated until afterthe pressure back I I has reached its final position against the platenH]. In other words, the pressure back may be engaged completely againstthe printing material and platen and all necessary adjustments madebefore the arms l2 are depressed further, in order to latch the pressureback in place and actuate the switch. This actuation of the lightingswitch on the up-stroke or return movement of the operating arms andhandle is an essential feature of the present invention and gives riseto the above mentioned advantages over the previously known forms ofconstruction. Since this particular actuation of the switch after thepressure back is completely in position, may be achieved by equivalentforms of construction readily apparent to those persons skilled in theart, it is not my intention to limit this invention to the preciseconstruction disclosed in the drawings. The invention should beinterpreted to include similar and equivalent arrangements within thespirit of the attached claims.

Now therefore I claim:

1. In a printing apparatus having a lamp house with printing lampstherein and a supporting platen thereon, the combination of a pressureback, an operating arm movably mounted with respect to said platen,means connecting said arm and back for movement of the latter into andout of engagement with the platen by operation of said arm, said armbeing movable toward the platen for a limited additional distance aftersaid back is in its final platen-engaging position, resilient meansopposing said additional movement, a latch member pivoted on said armfor movement between locking and releasing positions, a correspondinglocking element on said platen engaged by said latch member only whenthe latter is in looking position and said arm has been depressed saidadditional distance and released for partial return movement under theinfluence of said resilient means, and a switch operated by said latchto illuminate said lamps only on said return movement of the arm andlatch to locking position.

2. In a printing apparatus having a lamp house with printing lampstherein and a supporting platen thereon, the combination of a pressureback, an operating arm movably mounted with respect to said platen,means connecting said arm and back for movement of the latter into andout of engagement with the platen by operation of said arm, said armbeing movable toward the platen for a limited additional distance aftersaid back is in its final platen-engaging position, resilientmeans'opposing said additional movement, a latch member pivoted on saidarm for movement between locking and releasing positions, acorresponding locking element on said platen engaged by said latchmember only when the latter is in looking position and said arm has beendepressed said additional distance and released for partial returnmovement under the influence of said resilient means, a switch for saidlamps, and a movable switch actuating member mounted near said lockingelement and operated by said latch to illuminate said lamps only on saidreturn movement of the arm and latch to locking position.

3. In a printing apparatus having a lamp house with printing lampstherein and a supporting platen thereon, the combination of a pressureback, an operating arm movably mounted with corresponding lockingelement on said platen en- 10 gaged by said latch member only when thelatter is in looking position and said arm has been depressed saidadditional'distance and released for partial return movement under theinfluence of said resilient means, a pivotally mounted mercury switchoperated by said latch 'to illuminate said lamps only on said returnmovement of the arm and latch to locking position.

JOHN K. POLHEll/IU S.

